a1 Department of Human Nutritional Sciences, University of Manitoba, Winnipeg, Manitoba, Canada, R3T 2N2
a2 Community Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
a3 Department of Sociology, University of Winnipeg, Winnipeg, Manitoba, Canada
a4 Faculty of Health Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
a5 Centre for Food Policy, City University, London, UK
Objective The present study describes the trajectory of the energy gap (energy imbalance) in the Canadian population from 1976 to 2003, its temporal relationship to adult obesity, and estimates the relative contribution of energy availability and expenditure to the energy gap. It also assesses which foods contributed the most to changes in available energy over the study period.
Design Annual estimates of the energy gap were derived by subtracting population-adjusted per capita daily estimated energy requirements (derived from Dietary Reference Intakes) from per capita daily estimated energy available (obtained from food balance sheets). Food balance sheets were used to assess which foods contributed to changes in energy availability. Adult obesity rates were derived from six national surveys. The relationship to the energy gap was assessed through regression analysis.
Results Between 1976 and 2003, per capita daily estimated energy availability increased by 18 % (1744 kJ), and increased energy availability was the major driver of the increased energy gap. Salad oils, wheat flour, soft drinks and shortening accounted for the majority of the net increase in energy availability. Adult obesity was significantly correlated with the energy gap over the study period.
Conclusions The widening energy gap is being driven primarily by increased energy availability. The food commodities driving the widening energy gap are major ingredients in many energy-dense convenience foods, which are being consumed with increasing frequency in Canada. Policies to address population obesity must have a strong nutritional focus with the objective of decreasing energy consumption at the population level.
(Received October 18 2008)
(Accepted April 29 2009)
(Online publication June 17 2009)